1 Summary

This script runs analyses on data from study 1. Specifically, it compares data from three groups of participants who underwent escapable stress (EC), yoked inescapable stress (YC), or a control condition (CC), respectively. Here, we use the terms “group” and “condition” interchangeably. Measurements under investigation comprised reaction times (RTs) and ratings under acute stress (stressor aversiveness, control, exhaustion, frustration, helplessness) as well as pre-post changes in affective state (STADI and PANAS questionnaires), effects on working memory (reading span), and escape behaviour (activity, exploration, escapes, efficiency).

2 Sample Descriptives

In total, the sample consisted of N = 80 participants with n = 27 in CC, n = 27 in EC, and n = 26 in YC.

2.1 Age & Sex

3 A Priori Group Difference Checks

3.1 Sex (Chi-square Test)

## 
##  Pearson's Chi-squared test
## 
## data:  demo$condition and demo$sex
## X-squared = 0.03256, df = 2, p-value = 0.9839

There were no a priori group differences in male-female ratio.

3.2 Age (one-way ANOVA)

Because residuals were not normally distributed, we employed the Kruskal-Wallis test instead of a one-way ANOVA.

## 
##  Kruskal-Wallis rank sum test
## 
## data:  age_sess2 by condition
## Kruskal-Wallis chi-squared = 6.518, df = 2, p-value = 0.03843

There were some outliers and we checked for the 2 extreme cases but rerunning all analyses without those did not change the results, so we kept them.

3.3 Working Memory IQ (one-way ANOVA)

There were no outliers with respect to working memory IQ.

## Anova Table (Type 3 tests)
## 
## Response: workingmem_IQ
##      Effect    df    MSE    F pes p.value
## 1 condition 2, 77 140.03 0.81 .02     .45
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '+' 0.1 ' ' 1

There were no a priori group differences in working memory IQ.

3.4 Alertness (one-way ANOVA)

There were no outliers with respect to alertness.

## Anova Table (Type 3 tests)
## 
## Response: TAPalertness
##      Effect    df   MSE    F pes p.value
## 1 condition 2, 77 46.90 1.47 .04     .24
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '+' 0.1 ' ' 1

There were no a priori group differences in alertness.

4 Manipulation Check

4.1 Verify Yoking of Stress Durations

## 
##  Welch Two Sample t-test
## 
## data:  stress$stress_duration[stress$condition == "EC"] and stress$stress_duration[stress$condition == "YC"]
## t = -0.40496, df = 2111.3, p-value = 0.6855
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -0.06782429  0.04460753
## sample estimates:
## mean of x mean of y 
##  6.497424  6.509033

There were no differences in stress durations between EC and YC because YC participants were yoked to EC participants. Very slight timing inaccurracies are due to program execution differences. EC and CC performed at ceiling, responding fast enough to each cue as evidenced in mean stress duration well below the 15s maximum in each trial. Thus, there were no group differences in durations.

4.2 Stressor Aversiveness

There were outliers with particularly low aversiveness ratings which we excluded from this analysis because they affected the results. However, since they did not affect subsequent analyses, we included them in those.

## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##                 Sum Sq num Df Error SS den Df   F value  Pr(>F)    
## (Intercept)     5129.2      1   58.946     38 3306.6313 < 2e-16 ***
## condition          0.1      1   58.946     38    0.0417 0.83921    
## sex                4.1      1   58.946     38    2.6383 0.11258    
## trial              2.7      3   35.735    114    2.9027 0.03795 *  
## condition:trial    0.8      3   35.735    114    0.8176 0.48674    
## sex:trial          0.2      3   35.735    114    0.2084 0.89043    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##                 Test statistic    p-value
## trial                  0.49209 8.8335e-05
## condition:trial        0.49209 8.8335e-05
## sex:trial              0.49209 8.8335e-05
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##                  GG eps Pr(>F[GG])  
## trial           0.66826    0.06084 .
## condition:trial 0.66826    0.44560  
## sex:trial       0.66826    0.81288  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##                    HF eps Pr(>F[HF])
## trial           0.7055209 0.05769324
## condition:trial 0.7055209 0.45119097
## sex:trial       0.7055209 0.82429369
## Anova Table (Type 3 tests)
## 
## Response: aversive_rating
##            Effect          df  MSE      F  pes p.value
## 1       condition       1, 38 1.55   0.04 .001     .84
## 2             sex       1, 38 1.55   2.64  .06     .11
## 3           trial 2.00, 76.18 0.47 2.90 +  .07     .06
## 4 condition:trial 2.00, 76.18 0.47   0.82  .02     .45
## 5       sex:trial 2.00, 76.18 0.47   0.21 .005     .81
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '+' 0.1 ' ' 1
## 
## Sphericity correction method: GG
##  contrast  estimate    SE  df t.ratio p.value
##  X10 - X20  -0.2585 0.134 114 -1.927  0.2261 
##  X10 - X30  -0.3605 0.134 114 -2.686  0.0499 
##  X10 - X40  -0.3181 0.134 114 -2.370  0.0973 
##  X20 - X30  -0.1019 0.134 114 -0.759  1.0000 
##  X20 - X40  -0.0595 0.134 114 -0.443  1.0000 
##  X30 - X40   0.0424 0.134 114  0.316  1.0000 
## 
## Results are averaged over the levels of: condition, sex 
## P value adjustment: holm method for 6 tests

Both EC and YC rated the stressor as very aversive (global M = 5.744898). Mean aversiveness ratings did not differ between groups. Stressor aversiveness ratings slightly increased over time. There was no sex effect (at least not if outliers with very low ratings - who happened to be mostly male - were excluded).

4.3 Perceived Stressor Controllability

There were some outliers with respect to perceived control but excluding them did not affect results, so we kept them.

## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##                 Sum Sq num Df Error SS den Df  F value    Pr(>F)    
## (Intercept)     5577.1      1   751.14     76 564.2915 < 2.2e-16 ***
## condition        507.8      2   751.14     76  25.6912 2.997e-09 ***
## sex               19.3      1   751.14     76   1.9516   0.16648    
## trial              6.3      3   160.08    228   2.9718   0.03259 *  
## condition:trial    2.1      6   160.08    228   0.4994   0.80852    
## sex:trial          0.7      3   160.08    228   0.3391   0.79705    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##                 Test statistic    p-value
## trial                  0.35053 1.9017e-15
## condition:trial        0.35053 1.9017e-15
## sex:trial              0.35053 1.9017e-15
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##                  GG eps Pr(>F[GG])  
## trial           0.60946    0.05914 .
## condition:trial 0.60946    0.71985  
## sex:trial       0.60946    0.69360  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##                    HF eps Pr(>F[HF])
## trial           0.6237085 0.05786774
## condition:trial 0.6237085 0.72407621
## sex:trial       0.6237085 0.69859412
## Anova Table (Type 3 tests)
## 
## Response: control_rating
##            Effect           df  MSE         F  pes p.value
## 1       condition        2, 76 9.88 25.69 ***  .40  <.0001
## 2             sex        1, 76 9.88      1.95  .03     .17
## 3           trial 1.83, 138.96 1.15    2.97 +  .04     .06
## 4 condition:trial 3.66, 138.96 1.15      0.50  .01     .72
## 5       sex:trial 1.83, 138.96 1.15      0.34 .004     .69
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '+' 0.1 ' ' 1
## 
## Sphericity correction method: GG
##  contrast estimate    SE df t.ratio p.value
##  CC - EC      1.58 0.428 76 3.701   0.0008 
##  CC - YC      3.10 0.432 76 7.166   <.0001 
##  EC - YC      1.51 0.432 76 3.501   0.0008 
## 
## Results are averaged over the levels of: sex, trial 
## P value adjustment: holm method for 3 tests
##  contrast  estimate    SE  df t.ratio p.value
##  X10 - X20   0.2185 0.134 228 1.636   0.4127 
##  X10 - X30   0.3396 0.134 228 2.542   0.0584 
##  X10 - X40   0.3505 0.134 228 2.624   0.0556 
##  X20 - X30   0.1210 0.134 228 0.906   0.9726 
##  X20 - X40   0.1320 0.134 228 0.988   0.9726 
##  X30 - X40   0.0109 0.134 228 0.082   0.9726 
## 
## Results are averaged over the levels of: condition, sex 
## P value adjustment: holm method for 6 tests

We observed group differences in perceived control in the expected direction: YC reported lowest, EC middle, CC highest perceived control. There was a trend effect of time and perceived control decreased slightly over time.

5 RTs and Ratings During Stress Exposure

5.1 RTs

There were 2 outliers but only one was excluded from analysis due to exceptionally long RT.

## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##                    Sum Sq num Df Error SS den Df   F value    Pr(>F)    
## (Intercept)     487033208      1 10884357     72 3221.7238 < 2.2e-16 ***
## condition         1116499      2 10884357     72    3.6928   0.02973 *  
## sex                 94698      1 10884357     72    0.6264   0.43127    
## trial             1170370     39 21891749   2808    3.8492 1.791e-14 ***
## condition:trial    453502     78 21891749   2808    0.7458   0.95296    
## sex:trial          261886     39 21891749   2808    0.8613   0.71370    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##                 Test statistic    p-value
## trial               1.0643e-11 1.5261e-45
## condition:trial     1.0643e-11 1.5261e-45
## sex:trial           1.0643e-11 1.5261e-45
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##                  GG eps Pr(>F[GG])    
## trial           0.41001  4.583e-07 ***
## condition:trial 0.41001     0.8470    
## sex:trial       0.41001     0.6149    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##                    HF eps   Pr(>F[HF])
## trial           0.5334726 1.250428e-08
## condition:trial 0.5334726 8.828213e-01
## sex:trial       0.5334726 6.421118e-01
## Anova Table (Type 3 tests)
## 
## Response: rt
##            Effect             df       MSE        F  pes p.value
## 1       condition          2, 72 151171.62   3.69 *  .09     .03
## 2             sex          1, 72 151171.62     0.63 .009     .43
## 3           trial 15.99, 1151.31  19014.60 3.85 ***  .05  <.0001
## 4 condition:trial 31.98, 1151.31  19014.60     0.75  .02     .85
## 5       sex:trial 15.99, 1151.31  19014.60     0.86  .01     .61
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '+' 0.1 ' ' 1
## 
## Sphericity correction method: GG
##  contrast estimate   SE df t.ratio p.value
##  CC - EC     -30.2 17.1 72 -1.770  0.1618 
##  CC - YC     -46.4 17.4 72 -2.664  0.0286 
##  EC - YC     -16.2 17.4 72 -0.928  0.3566 
## 
## Results are averaged over the levels of: sex, trial 
## P value adjustment: holm method for 3 tests
## Call:
## bwtrim(formula = rt ~ condition * trial, id = ID, data = stress)
## 
##                   value df1      df2 p.value
## trial            2.9215  39 214.2123  0.0000
## condition       74.6689   2 465.4222  0.0000
## trial:condition  0.4669  78 278.6381  0.9999
## [1] -0.3888654
## [1] 1.01121

YC was significantly slower than CC but EC and CC did not differ in RTs. Overall RTs showed a steep decrease across the first few trials, then remained fairly constant.

5.2 Exhaustion

There were no outliers with respect to exhaustion ratings.

## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##                 Sum Sq num Df Error SS den Df  F value    Pr(>F)    
## (Intercept)     4310.7      1   734.92     76 445.7782 < 2.2e-16 ***
## condition        208.5      2   734.92     76  10.7821 7.549e-05 ***
## sex              107.1      1   734.92     76  11.0790  0.001348 ** 
## trial              6.8      3   107.20    228   4.7871  0.002964 ** 
## condition:trial    1.4      6   107.20    228   0.5114  0.799439    
## sex:trial          2.1      3   107.20    228   1.4547  0.227734    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##                 Test statistic    p-value
## trial                  0.48855 2.6448e-10
## condition:trial        0.48855 2.6448e-10
## sex:trial              0.48855 2.6448e-10
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##                  GG eps Pr(>F[GG])   
## trial           0.66064   0.009844 **
## condition:trial 0.66064   0.725800   
## sex:trial       0.66064   0.236790   
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##                    HF eps  Pr(>F[HF])
## trial           0.6782506 0.009244698
## condition:trial 0.6782506 0.730551927
## sex:trial       0.6782506 0.236495798
## Anova Table (Type 3 tests)
## 
## Response: exhausted_rating
##            Effect           df  MSE         F pes p.value
## 1       condition        2, 76 9.67 10.78 *** .22  <.0001
## 2             sex        1, 76 9.67  11.08 ** .13    .001
## 3           trial 1.98, 150.63 0.71   4.79 ** .06    .010
## 4 condition:trial 3.96, 150.63 0.71      0.51 .01     .73
## 5       sex:trial 1.98, 150.63 0.71      1.45 .02     .24
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '+' 0.1 ' ' 1
## 
## Sphericity correction method: GG
##  contrast estimate    SE df t.ratio p.value
##  CC - EC    -1.880 0.423 76 -4.442  0.0001 
##  CC - YC    -1.443 0.427 76 -3.376  0.0023 
##  EC - YC     0.437 0.427 76  1.023  0.3097 
## 
## Results are averaged over the levels of: sex, trial 
## P value adjustment: holm method for 3 tests
##  contrast  estimate    SE  df t.ratio p.value
##  X10 - X20  -0.1021 0.109 228 -0.934  0.7024 
##  X10 - X30  -0.3176 0.109 228 -2.905  0.0201 
##  X10 - X40  -0.3503 0.109 228 -3.205  0.0093 
##  X20 - X30  -0.2155 0.109 228 -1.971  0.1497 
##  X20 - X40  -0.2482 0.109 228 -2.271  0.0963 
##  X30 - X40  -0.0328 0.109 228 -0.300  0.7644 
## 
## Results are averaged over the levels of: condition, sex 
## P value adjustment: holm method for 6 tests

Both stress groups reported sig. greater exhaustion compared to the control group, however, they did not differ sig. from each other. Men in EC reported less exhaustion.

5.3 Frustration

There were a few outliers but none of them were extreme and excluding them did not affect overall results (although it improved statistical significance), so we kept them.

## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##                  Sum Sq num Df Error SS den Df  F value    Pr(>F)    
## (Intercept)     2782.69      1   649.52     76 325.6006 < 2.2e-16 ***
## condition        180.85      2   649.52     76  10.5805 8.835e-05 ***
## sex               82.07      1   649.52     76   9.6028 0.0027233 ** 
## trial             11.53      3   134.46    228   6.5195 0.0002999 ***
## condition:trial   10.70      6   134.46    228   3.0225 0.0073098 ** 
## sex:trial          0.48      3   134.46    228   0.2733 0.8446069    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##                 Test statistic   p-value
## trial                     0.73 0.0002693
## condition:trial           0.73 0.0002693
## sex:trial                 0.73 0.0002693
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##                  GG eps Pr(>F[GG])    
## trial           0.81419  0.0008414 ***
## condition:trial 0.81419  0.0126408 *  
## sex:trial       0.81419  0.8037775    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##                    HF eps   Pr(>F[HF])
## trial           0.8432281 0.0007157055
## condition:trial 0.8432281 0.0115972251
## sex:trial       0.8432281 0.8109732471
## Anova Table (Type 3 tests)
## 
## Response: frustrated_rating
##            Effect           df  MSE         F  pes p.value
## 1       condition        2, 76 8.55 10.58 ***  .22  <.0001
## 2             sex        1, 76 8.55   9.60 **  .11    .003
## 3           trial 2.44, 185.63 0.72  6.52 ***  .08   .0008
## 4 condition:trial 4.89, 185.63 0.72    3.02 *  .07     .01
## 5       sex:trial 2.44, 185.63 0.72      0.27 .004     .80
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '+' 0.1 ' ' 1
## 
## Sphericity correction method: GG
##  contrast estimate    SE df t.ratio p.value
##  CC - EC    -0.907 0.398 76 -2.281  0.0437 
##  CC - YC    -1.848 0.402 76 -4.600  <.0001 
##  EC - YC    -0.940 0.402 76 -2.341  0.0437 
## 
## Results are averaged over the levels of: sex, trial 
## P value adjustment: holm method for 3 tests
##  contrast  estimate    SE  df t.ratio p.value
##  X10 - X20   0.0101 0.122 228  0.083  1.0000 
##  X10 - X30  -0.3521 0.122 228 -2.877  0.0136 
##  X10 - X40  -0.4002 0.122 228 -3.269  0.0062 
##  X20 - X30  -0.3623 0.122 228 -2.959  0.0136 
##  X20 - X40  -0.4103 0.122 228 -3.352  0.0056 
##  X30 - X40  -0.0481 0.122 228 -0.393  1.0000 
## 
## Results are averaged over the levels of: condition, sex 
## P value adjustment: holm method for 6 tests

YC showed highest levels of frustration followed by EC, then CC. Only YC showed an increase in frustration over time. Men in EC reported less frustration.

5.4 Feelings of Helplessness

There were some outliers but excluding them did not change results in a meaningful way, so we kept them.

## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##                  Sum Sq num Df Error SS den Df  F value    Pr(>F)    
## (Intercept)     2930.50      1   697.44     76 319.3355 < 2.2e-16 ***
## condition        288.10      2   697.44     76  15.6971 1.966e-06 ***
## sex              100.85      1   697.44     76  10.9893  0.001406 ** 
## trial              1.06      3   162.89    228   0.4934  0.687182    
## condition:trial    7.74      6   162.89    228   1.8067  0.098696 .  
## sex:trial          0.17      3   162.89    228   0.0786  0.971566    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##                 Test statistic   p-value
## trial                  0.35139 2.078e-15
## condition:trial        0.35139 2.078e-15
## sex:trial              0.35139 2.078e-15
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##                  GG eps Pr(>F[GG])
## trial           0.58453     0.5871
## condition:trial 0.58453     0.1397
## sex:trial       0.58453     0.9029
## 
##                    HF eps Pr(>F[HF])
## trial           0.5972275  0.5910637
## condition:trial 0.5972275  0.1382201
## sex:trial       0.5972275  0.9066271
## Anova Table (Type 3 tests)
## 
## Response: helpless_rating
##            Effect           df  MSE         F  pes p.value
## 1       condition        2, 76 9.18 15.70 ***  .29  <.0001
## 2             sex        1, 76 9.18  10.99 **  .13    .001
## 3           trial 1.75, 133.27 1.22      0.49 .006     .59
## 4 condition:trial 3.51, 133.27 1.22      1.81  .05     .14
## 5       sex:trial 1.75, 133.27 1.22      0.08 .001     .90
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '+' 0.1 ' ' 1
## 
## Sphericity correction method: GG
##  contrast estimate    SE df t.ratio p.value
##  CC - EC    -1.611 0.412 76 -3.908  0.0004 
##  CC - YC    -2.258 0.416 76 -5.423  <.0001 
##  EC - YC    -0.646 0.416 76 -1.553  0.1246 
## 
## Results are averaged over the levels of: sex, trial 
## P value adjustment: holm method for 3 tests

Both stress groups reported sig. greater helplessness compared to the control group, however, they did not differ sig. from each other. Men in EC reported less helplessness.

6 Changes in Affective State

6.1 Depression and Anxiety (STADI)

We excluded two outliers with particularly high pre stress induction STADI scores that affected the results significantly.

## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##                Sum Sq num Df Error SS den Df   F value    Pr(>F)    
## (Intercept)    165639      1   3797.2     68 2966.2587 < 2.2e-16 ***
## condition          44      2   3797.2     68    0.3916 0.6774694    
## sex               552      1   3797.2     68    9.8863 0.0024687 ** 
## time              244      1   1171.6     68   14.1641 0.0003516 ***
## condition:time    142      2   1171.6     68    4.1277 0.0203285 *  
## sex:time           65      1   1171.6     68    3.7632 0.0565401 .  
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## Anova Table (Type 3 tests)
## 
## Response: STADI_S_Global
##           Effect    df   MSE         F pes p.value
## 1      condition 2, 68 55.84      0.39 .01     .68
## 2            sex 1, 68 55.84   9.89 ** .13    .002
## 3           time 1, 68 17.23 14.16 *** .17   .0004
## 4 condition:time 2, 68 17.23    4.13 * .11     .02
## 5       sex:time 1, 68 17.23    3.76 + .05     .06
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '+' 0.1 ' ' 1
##  contrast          estimate   SE  df t.ratio p.value
##  CC,pre - EC,pre      1.077 1.73 106  0.623  1.0000 
##  CC,pre - YC,pre      2.472 1.75 106  1.414  1.0000 
##  CC,pre - CC,post     0.174 1.17  68  0.148  1.0000 
##  CC,pre - EC,post    -2.840 1.73 106 -1.644  1.0000 
##  CC,pre - YC,post    -1.614 1.75 106 -0.923  1.0000 
##  EC,pre - YC,pre      1.395 1.77 106  0.790  1.0000 
##  EC,pre - CC,post    -0.903 1.73 106 -0.523  1.0000 
##  EC,pre - EC,post    -3.917 1.20  68 -3.269  0.0238 
##  EC,pre - YC,post    -2.690 1.77 106 -1.523  1.0000 
##  YC,pre - CC,post    -2.298 1.75 106 -1.314  1.0000 
##  YC,pre - EC,post    -5.311 1.77 106 -3.007  0.0428 
##  YC,pre - YC,post    -4.085 1.23  68 -3.329  0.0212 
##  CC,post - EC,post   -3.014 1.73 106 -1.745  1.0000 
##  CC,post - YC,post   -1.788 1.75 106 -1.023  1.0000 
##  EC,post - YC,post    1.226 1.77 106  0.694  1.0000 
## 
## Results are averaged over the levels of: sex 
## P value adjustment: holm method for 15 tests

Depressive mood and anxiety significantly increased from pre to post stress induction. A significant interaction of group x time indicated that this increase was limited to stress groups, whereas scores did not change in CC. Women in EC displayed greater increase in STADI scores compared to men.

6.2 Positive and Negative Mood (PANAS)

6.2.1 Positive Mood

There were two outliers but excluding them did not change results on positive mood changes, so we kept them.

## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##                Sum Sq num Df Error SS den Df   F value    Pr(>F)    
## (Intercept)    115675      1   5896.1     76 1491.0399 < 2.2e-16 ***
## condition          51      2   5896.1     76    0.3278   0.72149    
## sex               217      1   5896.1     76    2.7915   0.09888 .  
## time              546      1   1014.5     76   40.9117 1.177e-08 ***
## condition:time      8      2   1014.5     76    0.2860   0.75204    
## sex:time            1      1   1014.5     76    0.1021   0.75018    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## Anova Table (Type 3 tests)
## 
## Response: PANAS_pos
##           Effect    df   MSE         F  pes p.value
## 1      condition 2, 76 77.58      0.33 .009     .72
## 2            sex 1, 76 77.58    2.79 +  .04     .10
## 3           time 1, 76 13.35 40.91 ***  .35  <.0001
## 4 condition:time 2, 76 13.35      0.29 .007     .75
## 5       sex:time 1, 76 13.35      0.10 .001     .75
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '+' 0.1 ' ' 1

Across groups, positive mood decreased from pre to post stress exposure. No significant group differences were observed. There was a trend for sex effects with men in YC showing less decrease in positive mood from pre to post stress induction.

6.2.2 Negative Mood

There were some outliers with respect to negative mood but we did not exclude any participants.

## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##                 Sum Sq num Df Error SS den Df   F value    Pr(>F)    
## (Intercept)    22680.5      1   756.85     72 2157.6091 < 2.2e-16 ***
## condition         35.9      2   756.85     72    1.7074  0.188588    
## sex               97.8      1   756.85     72    9.3050  0.003198 ** 
## time              23.3      1   311.17     72    5.3974  0.022995 *  
## condition:time    44.2      2   311.17     72    5.1097  0.008412 ** 
## sex:time           7.6      1   311.17     72    1.7562  0.189286    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## Anova Table (Type 3 tests)
## 
## Response: PANAS_neg
##           Effect    df   MSE       F pes p.value
## 1      condition 2, 72 10.51    1.71 .05     .19
## 2            sex 1, 72 10.51 9.31 ** .11    .003
## 3           time 1, 72  4.32  5.40 * .07     .02
## 4 condition:time 2, 72  4.32 5.11 ** .12    .008
## 5       sex:time 1, 72  4.32    1.76 .02     .19
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '+' 0.1 ' ' 1
##  contrast          estimate    SE  df t.ratio p.value
##  CC,pre - EC,pre    0.00633 0.756 123  0.008  1.0000 
##  CC,pre - YC,pre    0.85950 0.771 123  1.115  1.0000 
##  CC,pre - CC,post   0.72690 0.577  72  1.259  1.0000 
##  CC,pre - EC,post  -1.53987 0.757 123 -2.035  0.4838 
##  CC,pre - YC,post  -0.68636 0.771 123 -0.890  1.0000 
##  EC,pre - YC,pre    0.85317 0.771 123  1.106  1.0000 
##  EC,pre - CC,post   0.72057 0.757 123  0.952  1.0000 
##  EC,pre - EC,post  -1.54620 0.579  72 -2.671  0.1216 
##  EC,pre - YC,post  -0.69269 0.772 123 -0.897  1.0000 
##  YC,pre - CC,post  -0.13260 0.771 123 -0.172  1.0000 
##  YC,pre - EC,post  -2.39937 0.772 123 -3.107  0.0352 
##  YC,pre - YC,post  -1.54586 0.601  72 -2.573  0.1457 
##  CC,post - EC,post -2.26677 0.756 123 -2.999  0.0459 
##  CC,post - YC,post -1.41326 0.771 123 -1.833  0.6919 
##  EC,post - YC,post  0.85351 0.771 123  1.107  1.0000 
## 
## Results are averaged over the levels of: sex 
## P value adjustment: holm method for 15 tests
## Call:
## bwtrim(formula = PANAS_neg ~ condition * time, id = ID, data = affStates_PANASneg)
## 
##                 value df1     df2 p.value
## condition      0.9831   2 29.2579  0.3862
## time           2.0266   1 41.2255  0.1621
## condition:time 5.8272   2 29.0161  0.0075

There were no sig. group differences but an overall increase in negative mood. Further, we observed a significant group x time interaction with EC showing an increase in negative mood, whereas the increase in YC did not reach significance and CC rather showed a decrease, albeit non-sig. Women in EC and YC reported greater increase in negative mood compared to men.

7 Escape Behaviour

7.1 Activity (moves per minute)

There were some outliers with respect to activity but none of them represented extreme deviations, so we kept them.

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## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##                  Sum Sq num Df Error SS den Df  F value    Pr(>F)    
## (Intercept)     1648831      1   333858     76 375.3423 < 2.2e-16 ***
## condition         12985      2   333858     76   1.4780  0.234584    
## sex                2396      1   333858     76   0.5455  0.462444    
## phase              9534      1    79136     76   9.1565  0.003381 ** 
## condition:phase    1063      2    79136     76   0.5105  0.602223    
## sex:phase           626      1    79136     76   0.6016  0.440370    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## Anova Table (Type 3 tests)
## 
## Response: mpm
##            Effect    df     MSE       F  pes p.value
## 1       condition 2, 76 4392.87    1.48  .04     .23
## 2             sex 1, 76 4392.87    0.55 .007     .46
## 3           phase 1, 76 1041.26 9.16 **  .11    .003
## 4 condition:phase 2, 76 1041.26    0.51  .01     .60
## 5       sex:phase 1, 76 1041.26    0.60 .008     .44
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '+' 0.1 ' ' 1
## Call:
## bwtrim(formula = mpm ~ condition * phase, id = ID, data = escapeBehav)
## 
##                  value df1      df2 p.value
## phase           6.4682   1 152.7970  0.0120
## condition       6.0699   2 140.9102  0.0030
## phase:condition 0.7066   2 140.9102  0.4951
## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##                        Sum Sq num Df Error SS den Df  F value    Pr(>F)    
## (Intercept)           8244154      1  1669291     76 375.3423 < 2.2e-16 ***
## condition               64925      2  1669291     76   1.4780  0.234584    
## sex                     11981      1  1669291     76   0.5455  0.462444    
## phase                   47671      1   395680     76   9.1565  0.003381 ** 
## condition:phase          5316      2   395680     76   0.5105  0.602223    
## sex:phase                3132      1   395680     76   0.6016  0.440370    
## trial                  151562      4  1415586    304   8.1371  3.03e-06 ***
## condition:trial         43398      8  1415586    304   1.1650  0.320047    
## sex:trial               52621      4  1415586    304   2.8251  0.025122 *  
## phase:trial             31718      4   693145    304   3.4777  0.008514 ** 
## condition:phase:trial   10871      8   693145    304   0.5960  0.781073    
## sex:phase:trial          2275      4   693145    304   0.2494  0.909913    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##                       Test statistic   p-value
## trial                        0.61935 0.0000459
## condition:trial              0.61935 0.0000459
## sex:trial                    0.61935 0.0000459
## phase:trial                  0.73366 0.0061037
## condition:phase:trial        0.73366 0.0061037
## sex:phase:trial              0.73366 0.0061037
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##                        GG eps Pr(>F[GG])    
## trial                 0.82862  1.648e-05 ***
## condition:trial       0.82862    0.32431    
## sex:trial             0.82862    0.03423 *  
## phase:trial           0.89703    0.01124 *  
## condition:phase:trial 0.89703    0.76314    
## sex:phase:trial       0.89703    0.89288    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##                          HF eps   Pr(>F[HF])
## trial                 0.8709214 1.083877e-05
## condition:trial       0.8709214 3.233215e-01
## sex:trial             0.8709214 3.170030e-02
## phase:trial           0.9469650 9.819693e-03
## condition:phase:trial 0.9469650 7.720967e-01
## sex:phase:trial       0.9469650 9.015552e-01
## Anova Table (Type 3 tests)
## 
## Response: mpm
##                   Effect           df      MSE        F  pes p.value
## 1              condition        2, 76 21964.36     1.48  .04     .23
## 2                    sex        1, 76 21964.36     0.55 .007     .46
## 3                  phase        1, 76  5206.31  9.16 **  .11    .003
## 4        condition:phase        2, 76  5206.31     0.51  .01     .60
## 5              sex:phase        1, 76  5206.31     0.60 .008     .44
## 6                  trial 3.31, 251.90  5619.66 8.14 ***  .10  <.0001
## 7        condition:trial 6.63, 251.90  5619.66     1.16  .03     .32
## 8              sex:trial 3.31, 251.90  5619.66   2.83 *  .04     .03
## 9            phase:trial 3.59, 272.70  2541.81   3.48 *  .04     .01
## 10 condition:phase:trial 7.18, 272.70  2541.81     0.60  .02     .76
## 11       sex:phase:trial 3.59, 272.70  2541.81     0.25 .003     .89
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '+' 0.1 ' ' 1
## 
## Sphericity correction method: GG
##  contrast estimate   SE  df t.ratio p.value
##  X1 - X2     -8.59 7.69 304 -1.117  1.0000 
##  X1 - X3    -29.71 7.69 304 -3.863  0.0011 
##  X1 - X4    -32.93 7.69 304 -4.282  0.0002 
##  X1 - X5    -33.23 7.69 304 -4.321  0.0002 
##  X2 - X3    -21.11 7.69 304 -2.745  0.0320 
##  X2 - X4    -24.34 7.69 304 -3.164  0.0105 
##  X2 - X5    -24.64 7.69 304 -3.203  0.0105 
##  X3 - X4     -3.22 7.69 304 -0.419  1.0000 
##  X3 - X5     -3.52 7.69 304 -0.458  1.0000 
##  X4 - X5     -0.30 7.69 304 -0.039  1.0000 
## 
## Results are averaged over the levels of: condition, sex, phase 
## P value adjustment: holm method for 10 tests

There were no group differences. Activity was greater in the free exploration phase, without stress exposure compared to the stress phase. Further, activity increased across trials, and differences between the phases were most pronounced at later stages of the experiment.

7.2 Escapes

There were no outliers with respect to number of escapes.

Because residuals were not normally distributed, we employed the Kruskal-Wallis test instead of a one-way ANOVA.

## 
##  Kruskal-Wallis rank sum test
## 
## data:  sum_escapes by condition
## Kruskal-Wallis chi-squared = 0.82641, df = 2, p-value = 0.6615

There were no significant group differences in escapes.

7.3 Exploration

There were some outliers with respect to exploration but none of them represented extreme deviations, so we kept them.

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## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##                  Sum Sq num Df Error SS den Df  F value  Pr(>F)    
## (Intercept)     1589304      1   286696     76 421.3072 < 2e-16 ***
## condition          7412      2   286696     76   0.9825 0.37909    
## sex                7277      1   286696     76   1.9291 0.16891    
## phase              3056      1    49554     76   4.6874 0.03352 *  
## condition:phase     979      2    49554     76   0.7507 0.47551    
## sex:phase           320      1    49554     76   0.4909 0.48568    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## Anova Table (Type 3 tests)
## 
## Response: exploration
##            Effect    df     MSE      F  pes p.value
## 1       condition 2, 76 3772.32   0.98  .03     .38
## 2             sex 1, 76 3772.32   1.93  .02     .17
## 3           phase 1, 76  652.02 4.69 *  .06     .03
## 4 condition:phase 2, 76  652.02   0.75  .02     .48
## 5       sex:phase 1, 76  652.02   0.49 .006     .49
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '+' 0.1 ' ' 1
## 
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
## 
##                        Sum Sq num Df Error SS den Df  F value    Pr(>F)    
## (Intercept)           7946520      1  1433480     76 421.3072 < 2.2e-16 ***
## condition               37062      2  1433480     76   0.9825   0.37909    
## sex                     36386      1  1433480     76   1.9291   0.16891    
## phase                   15282      1   247768     76   4.6874   0.03352 *  
## condition:phase          4895      2   247768     76   0.7507   0.47551    
## sex:phase                1600      1   247768     76   0.4909   0.48568    
## trial                  114702      4  1371034    304   6.3582 6.327e-05 ***
## condition:trial         37280      8  1371034    304   1.0333   0.41078    
## sex:trial               45495      4  1371034    304   2.5219   0.04117 *  
## phase:trial             11781      4   554970    304   1.6133   0.17076    
## condition:phase:trial    7944      8   554970    304   0.5439   0.82297    
## sex:phase:trial          2427      4   554970    304   0.3324   0.85609    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## 
## Mauchly Tests for Sphericity
## 
##                       Test statistic   p-value
## trial                        0.67206 0.0005201
## condition:trial              0.67206 0.0005201
## sex:trial                    0.67206 0.0005201
## phase:trial                  0.76083 0.0159433
## condition:phase:trial        0.76083 0.0159433
## sex:phase:trial              0.76083 0.0159433
## 
## 
## Greenhouse-Geisser and Huynh-Feldt Corrections
##  for Departure from Sphericity
## 
##                        GG eps Pr(>F[GG])    
## trial                 0.85457  0.0001766 ***
## condition:trial       0.85457  0.4075268    
## sex:trial             0.85457  0.0505343 .  
## phase:trial           0.90705  0.1767409    
## condition:phase:trial 0.90705  0.8067657    
## sex:phase:trial       0.90705  0.8384091    
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
##                          HF eps   Pr(>F[HF])
## trial                 0.8996985 0.0001283248
## condition:trial       0.8996985 0.4086527845
## sex:trial             0.8996985 0.0474113001
## phase:trial           0.9581431 0.1734359576
## condition:phase:trial 0.9581431 0.8159063382
## sex:phase:trial       0.9581431 0.8484354479
## Anova Table (Type 3 tests)
## 
## Response: exploration
##                   Effect           df      MSE        F  pes p.value
## 1              condition        2, 76 18861.58     0.98  .03     .38
## 2                    sex        1, 76 18861.58     1.93  .02     .17
## 3                  phase        1, 76  3260.11   4.69 *  .06     .03
## 4        condition:phase        2, 76  3260.11     0.75  .02     .48
## 5              sex:phase        1, 76  3260.11     0.49 .006     .49
## 6                  trial 3.42, 259.79  5277.50 6.36 ***  .08   .0002
## 7        condition:trial 6.84, 259.79  5277.50     1.03  .03     .41
## 8              sex:trial 3.42, 259.79  5277.50   2.52 +  .03     .05
## 9            phase:trial 3.63, 275.74  2012.64     1.61  .02     .18
## 10 condition:phase:trial 7.26, 275.74  2012.64     0.54  .01     .81
## 11       sex:phase:trial 3.63, 275.74  2012.64     0.33 .004     .84
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '+' 0.1 ' ' 1
## 
## Sphericity correction method: GG
##  contrast  estimate   SE  df t.ratio p.value
##  X1 - X2   -6.63383 7.57 304 -0.876  1.0000 
##  X1 - X3  -24.63596 7.57 304 -3.255  0.0101 
##  X1 - X4  -28.76343 7.57 304 -3.800  0.0017 
##  X1 - X5  -28.76005 7.57 304 -3.800  0.0017 
##  X2 - X3  -18.00213 7.57 304 -2.378  0.0900 
##  X2 - X4  -22.12960 7.57 304 -2.924  0.0260 
##  X2 - X5  -22.12623 7.57 304 -2.923  0.0260 
##  X3 - X4   -4.12747 7.57 304 -0.545  1.0000 
##  X3 - X5   -4.12409 7.57 304 -0.545  1.0000 
##  X4 - X5    0.00338 7.57 304  0.000  1.0000 
## 
## Results are averaged over the levels of: condition, sex, phase 
## P value adjustment: holm method for 10 tests

There were no significant group differences. Exploration was greater in the free exploration phase, without stress exposure compared to the stress phase. Also, exploration increased across trials.

7.4 Efficiency

There were some outliers with respect to efficiency but excluding them did not affect the results, so we kept them.

Because residuals were not normally distributed, we employed the Kruskal-Wallis test instead of a one-way ANOVA.

## 
##  Kruskal-Wallis rank sum test
## 
## data:  overall_efficiency by condition
## Kruskal-Wallis chi-squared = 2.5018, df = 2, p-value = 0.2863

Groups did not differ in behavioural efficiency.

8 Working Memory (Reading Span)

There were some outliers with respect to working memory PCL scores and we excluded them since this affected results significantly.

## Anova Table (Type 3 tests)
## 
## Response: pcl
##      Effect    df  MSE         F  pes p.value
## 1 condition 2, 67 0.01 10.01 ***  .23   .0002
## 2       sex 1, 67 0.01      0.08 .001     .78
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '+' 0.1 ' ' 1
##  contrast estimate     SE df t.ratio p.value
##  CC - EC    0.1345 0.0303 67  4.443  0.0001 
##  CC - YC    0.0515 0.0310 67  1.663  0.1011 
##  EC - YC   -0.0830 0.0313 67 -2.655  0.0198 
## 
## Results are averaged over the levels of: sex 
## P value adjustment: holm method for 3 tests

There was a significant main effect of group on working memory performance in the reading span test. EC participants performed signficantly worse than both YC and CC. The latter two groups did not differ.

9 Plots for Figure 1